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迎采窄煤柱巷道围岩控制技术研究 总被引:4,自引:4,他引:0
通过数值分析,研究了迎采窄煤柱宽度内应力场和位移场的分布规律,探讨了邻近工作面回采对巷道围岩稳定性、围岩变形的影响,并最终确定了合理的窄煤柱宽度,同时研究得到了高强锚杆锚索加固巷道围岩,重点加固窄煤柱帮的围岩控制技术。现场应用表明,合理留设迎采窄煤柱并采用高强锚杆锚索联合支护迎采窄煤柱巷道,经历两次采动影响后,巷道围岩顶底板和两帮变形量均300 mm,有效控制了围岩的大变形,技术经济效果显著。 相似文献
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Corrosion properties of friction-stir processed cast NiAl bronze 总被引:1,自引:0,他引:1
Friction-stir processing (FSP) was adopted to modify the microstructure of a cast Cu-9Al-4.5Ni-4Fe NiAl bronze alloy (NAB). After FSP, the initial coarse microstructure of the cast NAB was transformed to a fine structure, and the porosity defects were eliminated. The microstructure modification changed the corrosion behavior of the NAB in a 3.5% NaCl solution. In a static immersion corrosion test, the FSP NAB exhibited significantly greater corrosion resistance compared to the cast counterpart. The polarization curve and electrochemical impedance spectroscopic (EIS) results indicated that the FSP NAB showed slightly lower electrochemical corrosion resistance. 相似文献
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This paper presents a thermo-mechanical model to predict the thermal histories and the longitudinal residual stress difference at two sides of the butting surfaces using a factor named advancing retreating factor. This model allows taking into account of frictional heating dependent on both the temperature and the velocity of the tool, as well as heat generation due to plastic deformation dependent on temperature. The mechanical loads caused by the tool are added to the model for the mechanical analysis and the uncoupled thermo-mechanically equations are solved using a nonlinear finite element code ABAQUS. The numerical results showed that the longitudinal residual tensile stresses are asymmetrically distributed at different sides of the weld line due to the effect of the unsymmetrical temperature distribution and the tool forces. The calculated results have good agreement with experimental data that are presented in the literature. 相似文献
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凝汽器用多头螺旋槽管长度可达6~15m,两头是光管,中间有一段螺旋槽,因此其成形设备必须具有多头旋轧,非旋转式水平进料,螺旋槽部分长度自动控制、旋轮自动进给这4大特点,才能满足工业化应用的要求。该旋轧设备采用3个旋轮同时轧入,1道次成形;2个光电开关控制凸轮盘正、反转连锁实现旋轮自动进退,完成对螺旋槽部分长度的自动控制;利用前后张紧装置保证坯料在送料过程中不旋转。 相似文献
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厚铝合金板搅拌摩擦焊塑性金属不同深度的水平流动状况 总被引:11,自引:3,他引:11
通过在10mm厚LF2铝合金板的不同位置嵌入示踪Fe粉,进行搅拌摩擦焊对接实验,焊后截取不同深度的水平面试样,采用扫描电镜对试样进行能谱分析,通过观察Fe粉在焊缝金属中的水平分布,确定了10 mm厚LF2搅拌摩擦焊焊缝金属的二维水平流动状况.结果表明,塑性金属流动关于焊缝中心并不对称.焊缝下部金属受搅拌针作用,前进侧大部分金属与焊接方向相反向后流动,小部分金属向前流动,但都未进入返回侧;返回侧金属都向后流动,且有部分金属进入前进侧.焊缝上部金属主要受轴肩作用,前进侧大部分金属向前流动但未进入返回侧,小部分金属向后流动;返回侧金属沿旋转方向流入前进侧. 相似文献
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综采工作面末采期间回撤通道矿压显现规律及岩层控制研究 总被引:1,自引:0,他引:1
通过理论分析和现场观测,研究了补连塔煤矿采用辅巷多通道的回撤方式进行搬家倒面的矿压特征规律,介绍了综采工作面辅巷多通道主回撤区岩层控制的基本对策--主动支护和被动支护相结合,其中主动支护采用锚杆、锚索、网片等顶板加固来提高围岩自承能力的方法。这一研究成果可给同类条件下的矿井提供参考。 相似文献